- Fitting a 5.00 x 5 Nose Wheel to an RV9A

Last updated: 7 Aug 08 (Washers - changed from 2" to 50mm,12 aditional pages of documentation from Bill),27 June 08 (Tube solved, Tube supplier added, Reaming note, Bill advice on U-611 Disk Springs and Break Out force added, pictures added), 9 June 08 (Angle of attack measured), 3rd June 08 (Grease nipple tap size, Inner tube), 2nd June 08 (Correction Tips, Supplier added)

The measurements for the new wheel are:

14" diameter wheel.
5 1/2" clearance from bottom of leg to ground.
An extra 1 1/8" prop clearance.
An improved angle of attach. I only had a bubble level, the before and after shots are in the working pictures, but during weighing the angle was measured as 2.25 degrees tail down. Please measure yours before and let me know.

Bill's documentation:
Correction tips (new window).
Documentation (new window).
LAA Standard Mod Application (new window) Note: I used Bill's Mod number on the mod sheet and never applied for a mod.

Parts used:

  • New Vans' Nose leg.
  • Bill Knotts' Fork.
  • Vans' Bushings x 2. Possible to push old ones out.
  • AN6-60A Bolt, AN365-624 Nut and AN960-616 washer for axle. Same as Van's original.
  • 5.00 x 5 Tyre, Tube 5.00-5 Michelin Airstop 5CG67 (type111) Valve TR67 part no: 092-308-0. See 'Tube Valve' below.
  • 6 x 50mm diameter washers with 3/8" bore to act as spacers, required either side to fill aprox 3/16".
  • Internal Spacer - inside the wheel to keep the bearings properly spaced.
  • 2 x 5/16" UNF Bolts for anti rotation, cut to length of approx 1" with a slot cut in end to screw in.
  • 1 x Allen screw from old fork for Steering Stop.
  • Modify old steering stop, to accommodate one Allen screw stop and lower securing bolt to allow for higher new fork. Now new Swivel Stop instead.
  • Grease Nipple. Used the one in the Van's fork.

    • UK Suppliers (new window)

    Collection of parts

    Bits (82K)

Procedure:

Working Pictures (new window)

Excuse the mixed inches and millimeters, its just easier to use both.

  • Fit new Vans' Nose Leg.
  • As the fork is welded steel it may require checking for trueness, Bill has supplied some tips. Correction tips (new window). The fork welding may have distorted the tube, so after pressing in the bushings, ream to size.
  • Fit 5.00 x 5 Tyre and Tube to old wheel hub, with spacer in between wheel halves. The wheel is the same size as the mains so will take the 5" tyre.
  • Tap Steering stop hole, and the 2 anti rotation holes with 5/16" - 24 UNF tap. Tapping picture (new window)
  • Tap grease nipple hole with 1/4" - 28 UNF tap.
  • Drill washers to 3/8", they came with 1/4" hole.
  • Assemble wheel and fork. Mark Vans Axle Adapter U-623-1 (Spacer) and spacing washers with under sized drill through the forks anti rotation holes.
  • Remove Axle Adapters and with 6.5mm bit, drill them to 3/4" depth. Also drill washers. There will be several assembles and dissembles. Each time check the wheel internal spacer, it probably requires reducing, so do little at a time, and take advantage of the reassembles.
  • Make anti rotation screws, as I haven't a lathe I used AN5 bolts, cut the head off, put it in a drill press, made some soft wood spacers to protect thread, and let the file reduce the diameter from 5/16" (8mm) down to 6mm. Make sure the last thread or two are included as the thread is tapering at this point. Cut thread to give 3/16" length (width of fork), cut slot for screwdriver, cut to required length about 1", sorry I didn't measure this, but ensure it doesn't bottom out.
  • Weld lugs onto existing steering stop WD-631 with 1/8" 4130 steel, to change from two bolt stop to a one bolt stop. Weld up existing securing bolt holes and redrill lower. There is a lot of work cleaning up and reshaping the steering stop. I cut and prepared all the metal, including removing all paint to help cut the cost of welding. I later changed to the more sexy machined swivel stop as Bill's instructions. Picture in Working pictures.
  • Prep fork and paint.
  • Bill also helped with some good advice: The U-611 Disk Spring washers (the saucer shaped ones on the bottom of the leg), when new, these do not have a flat land area on the saucer bottom. I rubbed them on some emery cloth to create a small flat. Evidently if you don't do this they will wear very quickly and change the break out force. On the subject of the break out force, as the fork is longer Bill recommends that the break out force should be about 28 pounds on the axle.

    Tube Valve - The standard 5.00 x 5 tube from LAS or Watt's has a valve length of 57mm from the centre of the bend to the end, without cap, this puts the end 1/8" from the side of the fork, (without cap). The Van's main wheel valve looks at lot shorter, so may have to get a tube from them. Valve picture with 57mm valve.
    Solved by purchasing a very expensive £88 plus everything, special tube from Watts, with a 37mm angled valve, I understand these are made for gliders.

      Parts before assembly

      Parts (177K)

      Spat:

      First thought was the RV10 Spat as it accommodates a 5" wheel, but is 37" long and 16" high measured from the ground. This seems out of proportion to the 9s main spat.
      Second thought to split the 9A spat in half and fibre glass to shape - similar to Bills'. This way all the fittings are in place.

      To be continued.

    View Bill's LAA Standard Mod Application Click here (new window)

    Many thanks for the help and advice from Bill and other early adopters.

    Contact details: Norman Haines norman@manorfarmlea.com